Ixxv 



the effect of cold wet summers in producing blue females of 

 Lycaenidae : — 



" Notes on the effect of Climatic Conditions on Sexual 

 Dimorphism " (Trans. City of London Ent. Soc, 1908, xviii, 

 pp. 23-32). 



" Some notes on A. hellargus with references to allied 

 species " {Ihid., 1907, xvii, p. 43). 



The sudden appearance of the western hind-wing 



PATTERN IN MALES OF PaPILIO DARDANUS BrOWN, AT KiBWEZI, 



Kenya Colony. — Prof. Poulton exhibited the male specimen 

 referred to by Mr. W. Feather in the following letter, dated 

 August 27, 1922. Males from the West Coast (Lagos), W. 

 and E. Uganda, Nairobi, and Mombasa were also shown, 

 together with one possessing the tibtdlus Kirb. pattern, 

 collected by Dr. S. A. Neave at Kibwezi (about 3000 ft.), 

 April 2-4, 1911. 



" I am sending you a specimen of Papilio dardanus tihullus 

 which has the black band on hind-wing broken through by 

 yellow. Previous to 1922 I have never seen a specimen here 

 with the band thus interrupted. This year during the dry 

 season (from early May to the last week in October — if the 

 season is a normal one) all the specimens I have examined up 

 to the present date have had a most unusual amount of 

 yellow on the outer margin of the hind-wing. Now, the 

 place where tihullus occurs is ground that is covered by lava 

 rocks with underground water; consequently, the bush and 

 trees are in leaf all the year. So it is rather hard to see why 

 the dry season should affect this insect. I very seldom see a 

 specimen far from this lava-covered ground." 



Prof. Poulton said that it was difficult to believe that the 

 sudden appearance of these males at Kibwezi was due to the 

 dry season. East Africa with the most heavily marked males 

 {tihullus) was drier than West Africa with the less black 

 dardanus. The pattern of the latter form extended from the 

 West Coast to the high Kikuyu Escarpment in Kenya Colony, 

 where it appeared in the small mountain form polytrophus 

 Jord., possessing a male armature similar to that of the East 

 Coast tihullus. Transition between this and the dardanus 



